Electrical separator



Filed Nov. 20. 1931 Patented May 30, 1933 PATENT OFFICE FRANK F. STELZ, F JERSEY CITY, NEW JERSEY ELECTRICAL SEPARATOR Application 'filed November 20, 1931. Serial No. 576,272.

The object of the invention is to provide apparatus for carrying out an improved method of separating solid particles from any type of gases, such for instance as the gases which are given off from blast furnaces, cement making plants, chemical apparatus, etc., and which'carry with them dust that is detrimental to health and/or surrounding vegetation, or in many cases large quantities of valuable materials that would otherwise be, lost, but which upon being reclaimed provide by-products of sufficient quantity and value to materially add to the profits of a given industry.

Another object is more particularly to pro vide in such apparatus a combination of both mechanical and electrical means for accomplishing the desired separation of the particles from the gases, the electrical means in- 0 suring a great degree of separation through the medium of electrically charging the dust particles and thereby causing them to adhere to oppositely charged bodies, both stationary or movable, and the mechanical means in 5 this instance serving both to assist in such separation directly and to set up high frequency, low period vibrations which aid in precipitating the separated particles towards the bottom of the device.

A further object is to provide in the apparatus under discussion a rotatable member of suitable cross section. such as cylindrical, spherical, elliptical, or the like, comprising an outer perforated shell formed of suitable 5 mesh, or a perforated sheet metal drum as hereinafter described. while within this structure there are located a quantity-of articles which continuously change their relative positions and are adapted to create a tortuous path for gases passing substantially diametrically of the said member, while the articles in falling about as the member ro-.

tates cause sufficient vibration to aid in acceL crating the movement of the separated particles downwardly. Inthe preferred embodiment of the invention it has been found well to use short lengths of tubing, which, lying atvarious angles with-in the rotatable mem-- her and constantly falling over one another, 0 cause the dust-laden gases to pass in zig-zag .a drum surrounded by a series of discharge directions through said member, thereby tending to mechanically arrest the. movement of the solid particles, and electrically to cause them to adhere to the surfaces of said tubes whence they are jarredloose and settle into an operatively positioned hopper or other collecting device.

Still another object is to provide for maintaining the dust-laden gases at a predetermined temperattire while they pass through the device, it having been found that certain types of solidparticles. best precipitate at one temperature and someat another, while it is well known that the electric charging of the particles occurs to a maximum degree when the latter are entirely dry, so that while certain degrees .of moisture in the gas at the intake can be permitted, its effect should preferably be counteracted by maintaining a proper temperature of the gas while passing through and between the series of rotat- I able members.

And a still further object is to provide a modified form of separator member consisting of a series of spaced laminations, preferably of sheet metal and each of them so punched as to provide spaced lugs or flanges, arranged in every possible direction to offer a maximum of surfaceand an extremely zigzag path to all gases passing diametrically of the member,lfor the purposes hereinbefore referred to; and to provide in a still further modified form a separator unit comprising electrodes extending parallel with the axis of the drum, the drum itself being preferably perforated so as to leave many electrical discharge ears extending radially outwardly, as hereinafter described.

With these and other objects in mind, the present invention comprises further details of construction and operation which are fully brought out in the following description, whenread in conjunction with the accompanying drawing, in which Fig. 1 is a vertical section taken through a device embodying the present invention in one of its many forms; Fig. 2 is a fragmentary section on the line 22 of Fig. 1; Fig. 3 is a side elevation of a modified form of separator element; Fig. 4 is an enlarged detail view of one of the laminationsshown in Fig. 3; Fig.

5 is an end elevation of the same; Fig. 6 is a perspective view of one of the sections of 5 tubing employed in the separator elements shown in Figs. 1 and 2;Fig. 7 is a diagrammatic View showing the manner of electrically charging the device, to provide for electric precipitation of the dust particles from the dust-laden gases; Fig. 8 is a side elevation and Fig. 9 is a vertical section of a modified type of drum; and Figs. 10 and 11 are correspondingly similar views of a still further type of drum.

Referring to Figs. 1 to 7 of the drawing, a housing 1 of rectangular or other suitable cross section is shown as being supported upon standards 2, resting upon suitable foundation supports 3, between which latter car 5, beneath the discharge outlet 6 of a hopper 7, which forms a closure for the lower end of said housing.

Through a lower wall of said housing extends an intake aperture 8 by which dustladen gases enter the interior of the former from a blast furnace or other source (not shown). Within said housing adjacent to said intake, a channel 9 is provided between converging walls 10, which lead upwardly through a horizontally cylindrical section 11 of a casing to an outlet 12 between a diagonally extending deflector 13 and an oppositely positioned wall 14.

Within the casing section 11 there is mounted a cylindrical cage or the like 15, rotatable upon a shaft 16 in any suitable type of bearings 17, and separated electrically from the surrounding framework and housing by insulation 17', while beneath said cage the walls of said casing open downwardly into a pair of oppositely positioned converging walls 18 having an outlet 19 preferably above a spreader 20, this structure being operative to receive particles extracted from gas within the casing 11 by the cage 15 and to discharge them into the hopper 7 and car 5.

One form of cage is shown in Fig. 2 in detail, but it is to be understood that instead of a cage which is cylindrical in longitudinal cross section, the same may be spherical, clliptical, or otherwise, as may be desired, so long as the function of the same is preserved. The peripheral surface of such a cage is formed of a suitable gauze 21, or of any other structure provided with spaced apertures and adapted to retain therein a multitude of relatively small articles, such for instance as the short sections of tubing 22 shown in Fig. 6. 1 i

It will be seen that with the cage 15 filled to approximately 50% of its capacity with short pieces of hollow tubing in heterogeneous arrangement, and constantly altering their I relative positions as the cage slowly revglves,

is positioned a track 4, adapted to support a its contents, all of which are preferably of metal, an electrical charge, as by means of a wire 23 from the secondary 24 of a transformer (see Fig. 7), the other end of the said transformer secondary being connected by means of a wire 25 with the casing 11.

The transformer is of any suitable wellknown type having a primary 26 and energized from any suitable source of alternating current (not shown). As a result of this arrangement, the solid particles, particularly those of metal within the gases passing through the cage 15 become electrically charged and in well-known manner are attracted by the cage mesh 21 and the tubular elements 22 which are of the same polarity, thereby removing a greater quantity of dust particles than could be removed by the mechanical means alone.

As the gases from the casing 11 pass upwardly, they enter superimposed casings 27 and 28 within which respectively rotate the cages 29 and 30, while above the cage 29 there is a diagonally extending deflector 31 similar to the deflector 13, the latter being adapted to receive particles extracted from the gases by the cage 29 and the former receiving particles extracted by the cage 30, each of said last-named cages 29 and 30 being constructed, operated and electrically energized, as hereinbefore described with reference to the lowermost cage 15.

Above the cage 30 the gases, practically free ofall dust particles, pass into an exhaust chamber 32 and thence into a stack 33, whence they may pass byadamper34and outwardly to the atmosphere through a vent 35, or when said damper is closed, they may pass diagonally outwardly from i said stack through a channel 36, whence they are adapted to be lead to any other locality or container. For instance, if this discharge gas is of a combustible nature, it might be preferred to lead it into suitable apparatus for purifying or otherwise treating it before storing it for future use as might be desired.

Substantially on a level with the respective rotatable cages 15 and 29, the housing 1 is provided with outlets 37 and 38 opening respectively into chutes 39 and 40, said outlets being provided with pivotally mounted deflector-closures 41 and 42. vWhen it is desired 30 shall pass with those separated by the may pass between them.

cage 15 into the hopper 7, the closures 41 and 42 are raised into upright position, thereby closing their respective apertures and permitting the precipitated particles to pass by them downwardly into said hopper.

However, as the size of dust particles electrified by the several cages frequently vary to an appreciable degree, it is desirable under certain conditions to take the particles after electrification by each of the respective cages and instead of mixing them in the single hopper 7 to remove them directly from the separator housing 1, in which case either or both of the closures 41 and 42 are lowered so as to form substantial continuations of the respective deflectors 13 and 31, in which case dust particles precipitated upon the respective defiectors are conveyed by means of the closures, lowered into deflector positions, toward and thence through the chutes 39 and 40,

whence they may be transported by any desired means.

It has also been found that certain types of dust particles are more readily separated from the gases by which they are carried at a given temperature, and for this purpose the housing 1 is provided with an inlet 43 slightly above the intake 8 and with an outlet 44, so arranged'that either cold or hot air or other gas may be circulated through said inlet, upwardly in said housing to one .side ,of the separator elements 15, 29 and 30, and thence around the chamber 32 and downwardly to said outlet 44, positioned above the outlet 38. A closure 44, pivotally supported by the housing, serves either to close the outlet 44 and permit the temperature-.

regulating gases to ascend through the separator element'30 in the casing 28, or said closure in its lowered or open position forces these gases through said outlet without passing' through said element. The first arrangement is employed particularly when the gas entering the housing at 43 is from the same source as that entering at 8 and from all of which most if not all of the dust must be extracted.

Referring now to Figs. 3, 4 and 5 in particular, there is shown a modified form of separator which is intended to represent broadly a class in which there are no loose particles such as sections of tubing 22, but instead are found relatively fixed elements which in all positions of the separator op-- erate to create tortuous paths for the dustladen gases. A series of preferably metallic discs 45 are mounted upon a shaft46 and held together by any suitable fastening means, each of said sheets having stamped from within its body sections of metal, which.

when bent laterally outwardly form multidirectional ears or flanges 48, combining to form means for spacing said discs apart in predetermined relationship so that the gases This series of elements may then be surrounded by a mesh 49, if desired, and as the dust-laden gases pass through the separator element as a unit, the impetus given to the particles through the inertia imparted to them by the gases serves to buffet the former to and fro against said ears, and thus by impeding their progress with the relatively free-flowing gases, said element when electrically charged operates to both mechanically and electrically remove the particles from the gases.

Referring now to Figs. 8 and 9, a drum is shown as being formed of sheet metal, through which apertures 49 have been punched in such manner, and without re moval of the metal, as to provide a multitude of spurs 50, which when the drum is electrically charged serve as terminal points, to distribute the electric discharge as completely as possible about the circumference of the drum. Otherwise, the drum is mounted and operates as do the drums before described, and may be partly filled with solid particles, or may be empty asdesired. Finally, referring to Figs. 10 and-11, a modified form of separator unit is shown as comprising a drum 51 of either mesh, perforated sheet metal, or otherwise as may be preferred, the diameter of'such drum being considerably less than the inner diameter of the drum chambers 11, 27 and 28, andprovided upon its ends with circular plates 52 which extend radially well beyond the limits of the drum. Wires) 53, rods, or the like, are then positioned between spaced portions of the peripheries of said plates and shafts 5.4 upon which they are mounted, they (the wires) insure the elctrical charging of the entire air space between the drum and the adjacent sides of the drum chambers, thus insuring a more complete action of the high tension electric current upon and separation of the dust particles from the gases passing through such chambers.

In constructing and operating the improved separator as herein described, certain details have been found desirable or at least operate to advantage, although they are not necessarily mandatory. For instance, it has been found that the sizes'of the rotatable elements may be decreased upwardly through the series; the air gap between each of said elements and the adjacent wall surfac of its neighboring casing depends upon the voltage at which the apparatus is electrically charged; the separator element alone may be statically charged, instead of charging both the element and the surrounding casing; any number of stages of said elements may be employed the tubular particles within the several elements (where more than one element is used) may vary in size, as for instance, a preferred arrangement is to place ID, long sections of tubing in thelowermost element, ID, A to long sections in the uppermost of said elements; and the respective elements are preferably though not necessarily driven at a speed in the neighborhood of 4 to 5 R. I. M.

With this construction and improved method of operation, after passing the first stage approximately 35% of the dust particles have been removed from the original dust-laden gases, or about 65% by the use of mechanical and electrical means combined; after passing the second stage, these percentages are raised respectively to approximately 60% and 89%; while after passing the third and last stage, the percentages with the simultaneous use of both mechanical and electrical means will be found to have removed about 99.86% of the original quantity of dust; voltages of 50,000 to 150,000 or more being used, depending upon the particular gas, dust, temperature, humidity, etc., encountered.

The application of this invention in various industries is so wide as to include the treatment of smoke, particularly from bituminous coal and wood, chemical vapors, fumes and gases of all sorts, blast furnace gas as above referred to, cement, carbide, calcium and flour mills, foundries, graphite, lead, tin, copper, and alu'minunrsmelters, lime kilns, porcelain factories, etc.

The degree of gas purification or dust recovery which can be achieved with this invention, depends largely upon the velocity at WlllCll the gases pass through the electric Held, and the longer the time during which the gases are subjected at high velocity to the influence of said field, the higher the degree of purification. In one instance as an example, dust passing at 400 cu. mu-per minute has been extracted at 175 C. from the'gas from-a dry process cement manufacturing plant with the result that 98.58% recovery was attained, and an analysis showed this to be composed of SiO 32.06%; MnO, 0.18%; FeO, 2.12%; A1 0 12.01%; CaO, 45.30% MgO, 5.00% S, 1.67% BaO, 0.15%; and P 9 0.09% (total, 98.58%).

Having thus described my invention, what I clalin and desire to protect by Letters Pat ent of the United States is 1. In a dust extractor, a housing, a casing within said housing, a rotary separator element within said casing, a channel within said housing and outside of said casing to conduct a temperature-regulating fluid therethrough, and means to selectively prevent such fluid from entering said casing or to permit it to so enter and unite with dustladen gases also passing through said casing. 2. In a dust extractor, a housing,a series of rotary separator elements therein, com

ing and being connected together independent of and in spaced relation with said housing, an inlet and an outlet extending throu h said housing, each communicating with t e interior of said casings, and a separate inlet and a separate outlet to permit the passage of temperature-regulating fluid through said housing outside of said casings.

3. In a dust extractor, a housing, a series of rotary separator elements therein, communicating casing chambers within said housing and partially inclosing the respective elements, an inlet and an outlet through said housing, each connecting with the interior of said casings, a separate inlet and a separate outlet to permit the passage of temperatureregulating fluid through said housing outside of said casings, a connection between the interior of one of said casing chambers and the space between said casings and said housing and means to close said separate outlet or said connection selectively.

4. In a dust extractor, a casing, a rotatable element comprising a cage formed of a perforated peripheral covering, means within said cage to present a maximum of surface to dust-laden fluids passing therethrough, and means to electrically insulate said cage from said casing. I

1 5. In a dust extractor, the combination of a series of hollow rotary drums having perforated covers, a quantity of tubular elements loosely within each drum, the sizes of the tubes in the respective drums being different, means to conduct dust-laden gases through said drums successively, a casing surrounding saiddrums and in spaced relation therewith, and means to oppositely charge said drums and said casing electri ing from said elements, channels to prevent particles from the upper elements falling upon elements below them, outlets in said housing, and deflector-closures for said outlets, operative to close said outlets respectively and independently orto deflect falling particles through said outlets selectively.

7. A dust separator, comprising spaced discs mounted to rotate as a unit, and between which discs dust-laden gases are adapted to pass, a surrounding casing spaced from the peripheries of said discs, and means to charge said casing anddiscs with electric current at opposite potentials.

'8. A dust separator,'comprising discs having spacing ears punched outwardly from them to predetermine the separation of said discs and to provide passageways through said discs, a surrounding casing spaced from the peripheries of said discs, and means to charge said casing and discs with electric current at opposite potentials. a

9. A dust separator, comprisin a rotary element in turn comprisin tured drum, plates upon t e opposite ends, and of larger diameter than, said drum, electrical conductors extending between the peripheral portions of said plates and spaced radially away from said drum, a casing sur-.

rounding and spaced from said conductors, and means to electrically charge said drum, plates and conductors at an opposite potential from that of said casing.

10. A dust separator, comprising a rotary element in turn comprising a hollow apertured drum, plates upon the opposite ends, and of larger diameter than, said drum, electrical conductors extending between the peripheral portions of said plates and spaced radially away from said drum, a casing surrounding and spaced from sald conductors, and means to electrically charge said drum, plates and conductors at an opposite potential from that of said casing, the material removed from the perforation of said drum providing substantially pointed discharge terminals for the electric charge.

In testimony whereof I have afiixed my signature.

FRANK F. STELZ.

a ho low aper- 

